Stock ECU Temperature sensor voltage meaning

[reses]

I've been looking for the stock sensor values for a gauge project that I'm working on, the stock Oil pressure switch-sensor is a joke and I replaced that with a 0-150psi 5V one, but I was thinking of tapping the stock ECU temp sensor, in the Service Manual there is a little table that shows the relation between the Resistance and temperature





with that table I came with an equation that works for those values, but I don't know if that curve is good for 80C+ values (Or the stock sensor)


x<20
5.6-0.182826086956522 x+2.77555756156289 10^(-18) x^2+0.0000570652173913043 x^3

x<40
4.68695652173913-0.114347826086957 x+0.00342391304347826 (x-20)^2-0.0000478260869565217 (x-20)^3


2.49130434782609-0.0347826086956522 x+0.000554347826086957 (x-40)^2-0.00000461956521739131 (x-40)^3




Does the stock Coolant temp sensor have some usable range or is just like a Operating temp indicator (after 80-90C it just.. stays??), I have some data-logs but never seen that one go past 90s.

If that one is "good" how do you know the voltage-temp relation, stand alone guys need to setup this right?

[Chris@Rvengeperformance]

if you have chrome there is a table called "Coolant Temp Sensor Scaling" that has what I understand to be the voltage to temperature scale. it is a really wide table, has numbers about every 2 degrees.

[reses]

Thats great, thanks for the tip, I don't have chrome but I guess that I can take a look at that one, I have two stock 99 vr4/SL bin files (from the EvoScan site).

[reses]

I don't see the temp scaling in the 99 ROM definition but I took a look at the EVO 9 rom coolant temp scaling table, should be similar, the MD177572 is also 3S compatible.

[Chris@Rvengeperformance]

I don't see the temp scaling in the 99 ROM definition but I took a look at the EVO 9 rom coolant temp scaling table, should be similar, the MD177572 is also 3S compatible.

its probably only in greg's definition file.

[Greg E]

I don't see the temp scaling in the 99 ROM definition but I took a look at the EVO 9 rom coolant temp scaling table, should be similar, the MD177572 is also 3S compatible.

They are similar but not the same.

Also, there are two coolant sensors on the thermostat housing (for 2G cars anyway). One for the gauge, one for the ECU.

[reses]

Yeah, I'm looking at the ECU, the one for the gauge is useless, I don't have any info about the temp-range on that one, the Evo one shows a 167-element scaling table for its sensor

0.215053763v = 126C
.
.
4.545454545 = -40C